ABSTRACT: Detection of Liquid Hydrocarbon Seepage in Indonesia Offshore Frontier Basins Using Airborne Laser Fluoresensor (ALF) -- The Results of a Pertamina/BP Joint Study

MACGREGOR, D., and G. NEWCOMBE,* BP Exploration, Jakarta, Indonesia, J. PURNOMO and C. REMINGTON, Pertamina, Jakarta, Indonesia, and M. THOMPSON, BP Exploration, Jakarta, Indonesia

Statistics indicate that most onshore sedimentary basins with significant hydrocarbon production or discoveries show evidence of seepage. In unexplored offshore basins the ability to detect seeping hydrocarbons is crucial to establishing an active source system. BP Research in conjunction with BP Exploration (BPX) have developed the Airborne Laser Fluorosensor (ALF) to detect the presence of such leakage at the sea surface.

In response to a Pertamina proposal, and on their behalf, BPX acquired ALF surveys over several unlicensed frontier basins in Indonesia. me aim of the study was to determine whether hydrocarbons were leaking from these basins, thus significantly lowering source risk, and hence promoting future exploration activity in these areas.

During a six-month period (first and second quarter, 1991), Pertamina/BPX acquired ALF surveys over: Sumatra Forearc basin; Java Forearc basin; Billiton basin; Salayar, Spermonde, South and North Makassar basin; Bone basin; Gorontalo basin; Halmahera.

Interpretation of the results suggest hydrocarbons are seeping to a variable extent from all of these basins, with the exception of the Java forearcs, though further analysis is required in some areas to confirm this. Geological models are proposed to explain the pattern of interpreted seepage. The areas of greatest potential interest are the Billiton, southern Bone and south Makassar basins.

AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)